Paradoxically, shingling of streams to this very day, and after many decades, is seen as a fundamentally important “inline” process for web printing which is almost always accomplished as the final operation of conventional “inline” folder machines. While it is unclear why it is that shingling gained such pre-eminence, it seems that shingling started out decades ago as a means to handle increased production seeds. After all, a single-file stream spaced by a copy's width typically travels at a surface speed that are six times higher, or more, than shingled copies with a two-inch shingle pitch. As the years passed, the evolution of folders, trimmers and stackers assumed that the incoming stream of copies to be processed would be shingled. Further, the shingling apparatus of preference is a sub-assembly section of conventional folder machines, called a fly shingling apparatus (also called a fan or spider or star delivery system). The fly is an entrenched industry standard even though it is heavily reliant on precise mechanical timing such that it contributes to lower production speeds which can be as low as 50% of the design speeds of the web press which it serves. As a result of fly shingling and its historic importance to the web printing process, inline folder machines, and other finishing equipment such as trimmers and stackers, are designed around the accepted idea that stream shingling was a mandatory processing step in web printing and that shingling was necessarily done at the folder machine. However, U.S. Pat. No. 5,833,226 issued Nov. 10, 1998 entitled “Inline Deserter and Integrator Apparatus and Method” assigned to the same assignee as the present invention broke with this convention of fly shingling at the folder machine by introducing a method of shingling without its mechanical timing proclivities and without it being necessary to perform this shingling at the folder machine. This prior art was the first step taken towards shingling as a distinct and separate operation from the folder machine even though this prior art only contemplated receiving shingled stream(s) to reform them into a single shingled stream. This prior art teaches a method and apparatus to generate a single shingled stream from a nested shingled stream or two shingled stream, by creating a shingle single-file stream and then re-shingle the stream into a single shingled stream.
With regards to shingling at a folder machine by other means than a fly, U.S. Pat. No. 5,102,111 dated Apr. 7, 1992 assigned to Heidelberg Druckmaschenen AG entitled “Folder for a print machine” introduces a shingling device that relies on a gripper device to de-accelerate books where the gripper device must be mechanically timed to the press speed. This art may be superior to the conventional fly systems. However, both are mechanical timed devices, a process negative. In passing, as will be pointed out later more fully, the operations of cutting and folding of a folder machine are very precise during which each copy is firmly controlled. This precision lends itself to a highly symmetrical flow of copies, which is ideal for any timing sensitive subsequent process such as shingling. Thus U.S. Pat. No. 5,102,111 is very similar to U.S. Pat. No. 3,994,221 dated Nov. 30, 1976 issued to F. John Littleton, Effingham, Ill. and U.S. Pat. No. 4,040,617 dated Aug. 9, 1977 issued to Colin Walkington of Bristol, England in that all three rely a direct timing relationship to cutting cylinder of a folder machine. In a true sense, their mechanical timing proclivity is quite similar to that of the fly shingling apparatus and its operational negativeness in terms of reliability, dependability and limited production speed.
In the printing industry, a rotary printing “web” press typically has one or more folder machines at its discharge. A typical folder machine is one that receives ribbons of paper and performs the operations of cutting the ribbons into equal lengths, folding each length and delivering each folded length as a printed product in a shingled stream on an exiting conveyor. A printed product of one or more folded sheets is commonly called a book (or signature). When a “book” is folded only once, such as one section of a newspaper, it is referred to as a half-fold book. When a half-fold book is folded a second time, perpendicular to the first fold line, it is referred to as a quarter-fold book. Both half-fold and quarter-fold books may be created “in-line”into a wide number of products by folder machines. Once the “in-line” books are half-folded and/or quarter-folded, they are typically issued to a fly shingling apparatus of a folder machine in a single-file stream and exits in a very specific format called a shingled stream. A typical shingled stream of books is one where the next book is resting squarely on top of the prior book, and so on, on a conveyor as they exit the folder machine. However, the leading edge of the next book is behind the leading edge of the prior book by two to four inches and so on. A good comparative imagery of a shingled stream of book is the conventional arrangement of roofing shingles on a sloped domestic roof where the roofing shingles at the lowest elevation is comparable to the forward end of a shingled stream of books issue from a folder machine. Almost unanimously, the leading edge of the books in a shingled stream is their backbone. The backbone of a book is the line, and the edge, of the last fold put into it at the folder machine. As an example, if you are reading the front page of a conventional North American newspaper, a half-fold product, without opening its first page, the “last” (and only) folded edge is at your left-hand side. This folded edge is the half-fold backbone of that book. The tail of that book is the opposite side on your right side; a collection of page ends. The width of this half-fold book is its height or the length of the backbone line. Its length is the distance from the backbone line to the tail end. The cut-off length of the press and folder machine is twice the length of a half-fold copy. Typically, a web printing press and folder have a single cut-off length since the requirement of precision in cutting and folding dictates fixed machinery components.
Increasingly in the web printing industry two, or more, books are issued as a set of books from the cutting and folding operations of folder machine in a nested array and delivered in a shingled stream as if each set was a single book. As a visual aid to this interesting idea of nesting books, assume that the above mentioned newspaper had three sections, A, B and C. Each section can be said to be an individual book where book C is inserted into book B and book B is inserted in book A. As you hold this whole newspaper closed on a table in front of you as if you were reading the front page of book A, move book B and C away from you as one piece so that their backbone is still against the backbone of book A and so that the books B and C protrude approximately by two inches beyond the top edge of book A. Now, move book C without moving books A and B so that it protrudes by two inches above book B. This arrangement of books is one set of three nested books. This nested book arrangement is achieved from a web press by misaligning the ribbons of book C relative to the ribbons of book B and those of book B relative to book A before the folder machine. In this way, books A, B and C are folded simultaneously as if they were one book. Similar to the above description of a shingled stream, a single shingled stream of nested books is one where one set of nested books rests squarely on another set except that the common backbone of each set is two to four inches apart. This distance between the backbone edge of books in a shingle stream is called the shingle pitch (P). The purpose of nesting books is to optimize the full width of a printing press. Web presses are purchased in assorted web widths ranging from 12 to 70 inches. A popular width is 36 inches. Often, a given printing run cannot use the full width of a press. Because of this fact, it used to be very common to see web presses running using paper widths that are 50% or 60% of the width of a web press. Rather than using less than the full web width of a press, nesting is a practical and powerful means to increase production rates by up to 100% by delivering a book of each set of two nested books to its own separate flow line. Nested book may be two or more similar or dissimilar books. Typically, a print run of 300,000 copies operates at 30,000 copies per hour (ch) can be run nested, the press-time to complete it will be 5 hours rather than 10 hours at $300-400 per hour machine-time, the savings is $1,500-2,000 for this single press run or as much as $1,000,000 per year.
A half-fold book produced “in-line” on a web press is the result of multi-colour printing on both sides from the unravelling of a wide large roll of paper. This continuous sheet of paper is threaded through multiple printing press units (one press unit per process ink colour—i.e. black, yellow, blue and red) from a roll of paper. This length of paper is commonly called the primary web. After this primary web is fully printed, that is, all ink colors are applied, it is usually slit at desired locations parallel to the sides of the primary web to result in secondary webs. A secondary web is commonly called a ribbon. Each ribbon is then threaded so that one is placed precisely on top of others prior to a folder machine. These ribbons may be aligned or misaligned in numerous different ways to achieve many desired results at the folder machine. A simple half-fold conventional folder machine can generate a single-file stream of books, nested or not and then shingle the books. More complex folder designs are capable to generate a single-file stream of half-fold books and then quarter-fold the books in line. If such a complex dual folder is not available to a printer and his customer wants a quarter-folded book, the half-fold books from a simple folder machine must be re-processed off-line. This is very costly.
Other special folder machines are capable to generate two (or more) half-fold or quarter-fold shingled streams nested or not. For the present purposes, it is not relevant to explain how the manipulation and arrangement of ribbons may result in the simultaneous production of multiple books exiting in a single or multiple shingled streams. However, it is important to understand that each stream of books must exit the cutting and folding operations of any folder machine in a consistent and orderly sequential manner; a precise symmetry of exiting books imposed by the folder machine design. Also, it is important to know that, almost without exception, folder machine designs are fundamentally similar. A single width simple folder machine delivers one stream of books in a single-file stream after cutting and half-folding with a very high level of book symmetry. That is to say that the books flow forward in a straight line with a constant precise cutting and half-folding operation can be done on a double-width cylindrical folder rollers to process two sets of ribbons, side by side, to result in two streams of books simultaneously, side by side.
Alternatively, the folder machine may be double-circumference cylinder folder roller to generate two half-fold books at once from each set of ribbons to result in two streams of books simultaneously, one above the other. When a folder machine issues two streams, each stream possesses a precise symmetry of books (well aligned with one another and spaced apart identically). More importantly, the books of each stream are in perfect symmetry with one another (one book of each set cut and folded at the folder machine is spatially fixed in relationship to the other). This precision in book symmetry must exist. If it did not exist, book jams would occur. Given the high speeds of present-day web printing, a single book jam could be very onerous in terms of lost production and serious folder machine damage.
To generate this precision of the cutting and folding operations in a folder machine, the ribbons (and half-fold books issued from them) are continuously and securely pinned at all times. This fact lends itself to excellent symmetry of books. However, once books of a stream enter the standard fly shingling section of a folder machine, this symmetry of books is made less perfect by the requirement to process each book, one at a time, without full pinning control since this art of shingling involves putting each book into free flight and then stopping each one abruptly. While this fly shingling art is subject to a wealth of refining arts, none of these overcome its fundamental operational negatives of free projectile flight, severe mechanical timing proclivities and the risk of book skewing due to full stoppage of each book.
Let us take a closer look at a web press set-up with a simple folder machine that only half-folds. Also, let us assume that each book produced is made of four nine inches wide ribbons using twenty-four linear inches of each ribbon per book to be folded once at the centerline of its 24 inch width. Each set of sheets cut from these ribbons is a half-folded into a book. This book consists of 8 half-sheets printed on both sides. This book is called a 16-page tab. If this 16 page tab print run was abruptly stopped without breaking any of the four ribbons, the four ribbons immediately prior to the folding and cutting operations of the folder machine would be observed to be in perfect page symmetry. The first purpose of the folder machine is to cut this set of four ribbons sequentially at pre-set points into twenty-four inch lengths. This 24-inch length is called the “cut-off” of the folder machine and the “cut-off” of the press it serves. Typically, each folder machine and web press has a common cut-off length.
The second purpose of this folder machine is to half-fold each set of the four ribbons simultaneous in unison with the above mentioned cutting operation.
The third purpose of the folder machine is to reform the single-file of half-folded books that results from the two prior operations into a single shingled stream. To accomplish the first two purposes of the folder machine, one popular prior art is to accurately and consistently feed this set of four ribbons to a folding cylindrical roller in which there is mounted a precisely timed knife to cut the ribbons. Also, there is lateral cavity in the cylindrical roller to create the center-line of the book being cut. Simultaneously, the book being cut is tucked into this lateral cavity to break the tensile strength of the ribbons and to grip that book securely at its new half-fold line (its backbone). This new book travels securely pinned around the circumference of the cylindrical roller and exits between a nipping roller set assembly that permanently creases the four sheets at its half-fold backbone and move it safely away before the next book arrives. Unless the forward speed of the half-fold books are increased or decreased after they are released from the jaw of the lateral cavity in the cylindrical roller, the stream of half-fold books issued from nipping roller assembly will be in a single-file stream of books spaced, one after the next, by the width of one book. In all cases, this stream of books has perfect internal book symmetry. If it did not, the process of cutting and folding would be too fragile to operate at modern high production speeds of 8 to 25 half-fold books per second. Accordingly, all designs of folder machines are precisely mechanical timed operation of cutting, tucking and half-folding devices achieved while maintaining each book under full-pinned control.
In other more complex folder machines, the symmetry of exiting books may be different than explained above. However, the symmetry of exiting books must also be flawless prior to the shingling operation. Other typically symmetries are (1) two single file streams, one immediately over the other, where one stream of books is precisely and steadily out of phase with the other and (2) two single-file streams, side by side, where the books of both streams are in perfect phase with one another. This term “book phasing” is about the position of each book of the pair of books simultaneously cut and folded as they exit the half-fold section of the folder machine.
Unfortunately, the conventional practice of the printing industry to immediately convert each single-file stream of books of a folder machine into a shingled stream using a fly shingling apparatus of the folder machine tends to reduce the degree of perfect book symmetry that existed.
It would be useful to analyse the design of a fly shingling apparatus of a conventional folder machine to better understand its limitations relative to the flyless shingler section of the machine assembly of the present invention.
A conventional fly shingling assembly is a standard final operation of a folder machine. It is a device that receives the orderly and fully controlled single-file stream of half-fold or quarter-fold books with their last backbone forward after the prior cutting and folding operations of the folder machine to reform the books into a shingled stream. While there is a host of prior art to improve control over the free flight of each book entering a fly shingling apparatus, it is impossible to totally eliminate this negative feature of turning a single-file stream of a fully pinned book into a free flight projectile, one by one. First, the books typically travel horizontally before the fly shingling apparatus in a single-file stream. Then, each book is re-directed downwards into a V-segment of the rotating flywheel of the fly shingling apparatus. First, one V-shaped segment catches and stops one book once it is released (unpinned) and the next V-segment catches the next book and so on. Second, each V-segment rotates to move the prior book of the single-file stream out of harm's way before the next book arrives at the next V-segment. The fundamental reality of these three operations (catching, stopping and rotating each book) is that the pinning control over each book in a single-file stream cannot continue as each enters into its V-segment. Further, the production speed at which these three fundamental operations must be performed is as much as 70,000 ch (copies per hour) or about 20 books per second. The commonly accepted maximum speed limit for a conventional single stream fly shingling system is approximately 35,000 ch. Because of this, most presses are slowed down to avoid product jams at the flywheel of the associated fly shingling apparatus.
Essentially, all designs of these flywheels are similar. In design, they are like a series of adjacent bicycle wheels mounted one beside the other on a common shaft that is turning clockwise to receive the flow of incoming single-file books at about 2 o'clock from above. These bicycle wheels have no rims/tires and the spokes are severely bent backwards as if they were flexibly bent by the centrifugal force of this clockwise rotating flywheel assembly. A V-segment is formed by two adjacent spokes of each adjacent bicycle wheel that are in perfect alignment with each other. This creates a distorted V-segment pocket to receive and catch one book as the fly assembly rotates clockwise. Once one book is caught in one V-segment of these flywheel fingers, this circular assembly is precisely rotated so that the next V-segment is positioned to receive and catch the next book and so on. Sequentially, the forward surface speed of each book is stopped in its V-segment of the flywheel at the apex of each V-segment and then it is deposited on an exiting conveyor stationed just below the flywheel to move the books tangentially and shingled. The surface speed of the exiting conveyor is set so that the backbone of the next book is laid down about 2 to 4 inches (Shingle Pitch) behind the backbone of the prior book and so on. Of course, this surface speed of the exiting conveyor determines the actual shingle pitch.
Conventionally, two sets of finishing equipment and two sets of staff are required to trim/stack two streams of books. Two sets of finishing equipment can cost between $200,000 to $600,000 per stream. The typical staff costs for one or two person per book stream can cost between $350,000 and $700,000 US per year in the United States.
However, when the nested sets of books are two different products, it is necessary to have two separate streams and two sets of finishing equipment/staff. The preferred embodiment of the present invention permits that a nested stream by reformed into one or two streams as requires from print-run to print-run without duplicity of desertion equipment and without wasting press-time to convert from one or two streams et-up to the other set-up. Equally important, double-width and double circumference folder machines were conceived to make use of two fly shingling units simultaneously to result in higher production yields than possible from a single fly at 35,000 ch.